1. Field of the Invention
This invention relates to spacesuits and in particular to apparatus which can be used to: (1) adjust the length of various portions of a spacesuit so that the spacesuit can fit a variety of users; (2) relieve loads applied to the spacesuit during use by an astronaut, i.e., relieve the forces on a spacesuit known as "manloads"; and (3) provide rotation of spacesuit components relative to one another, i.e., serve as a bearing.
2. Description of the Prior Art
FIG. 1 shows a representative spacesuit which includes helmet 10, rear entry panel 12, main body 14, shoulder portions 16, arm portions 18, gloves 20, hip portions 22, leg portions 24, and boots 26.
To accommodate users of different sizes, prior art spacesuits have employed various approaches for adjusting the size of the spacesuit to fit the user, e.g., to adjust the lengths of arm portions 18 and leg portions 24. Commonly-assigned U.S. Pat. No. 5,068,919, the contents of which are incorporated herein by reference, reviews these prior approaches, including the use of sewn-in fabric inserts in the arms and legs of the suit and the use of metal sizing rings held in place by Ortman wires.
U.S. Pat. No. 5,068,919 itself discloses an improvement over the Ortman approach in which the Ortman wires are replaced with threaded collars, a threaded metal sizing ring, and a redundant interlock system to prevent inadvertent disassembly of the components. The system of this patent has proved to be highly successful in practice.
Further improvements, however, are desired in a number of areas. First, none of the prior approaches to spacesuit sizing has provided automatic sizing during use. Rather, all of these approaches have required that sizing be performed before an astronaut suits up. Accordingly, two astronauts can rarely use the same spacesuit without first going through a sizing procedure on the suit.
Similarly, none of the prior spacesuit sizing approaches has provided relief for loads applied to the spacesuit during use. Such loading can, for example, occur when an astronaut spreads his or her arms to their full extent while performing maneuvers in space. This loading can be significant especially if the astronaut's personal preference is for a spacesuit which is rather tight fitting. As known in the art, an astronaut will experiment with a number of spacesuit components to find a spacesuit size which he or she finds suitable. This process can result in a suit which has a fingertip to fingertip length which is shorter than the astronaut's maximum extended arm length by, for example, one inch (2.54 cm). Accordingly, when an astronaut spreads his or her arms to their full extent significant loads (manloads) can be applied to the suit.
The prior approaches to spacesuit sizing have also employed components which were not free to rotate relative to one another during use. Accordingly, separate components have been required to provide bearing function at, for example, the shoulder, elbow, hip, and knee joints. This separation of sizing and bearing function has increased the cost and complexity of the spacesuit.